I need function pointers!!!

Comments

• wjsteele Posts: 697

  2011-01-27 13:50 edited 2011-01-27 13:50

  I thought someone hacked them into some sample code a while back... perhaps it was the Beau himself?
  
  Bill
• RobotWorkshop Posts: 2,307

  2011-01-27 13:58 edited 2011-01-27 13:58

  Is this the thread you were referring to?
  
  http://forums.parallax.com/showthread.php?127057-DEMO-Self-Modify-Spin-Code-Example&highlight=pointers
• Dave Hein Posts: 6,347

  2011-01-27 14:07 edited 2011-01-27 14:07

  Kye,
  
  I posted a MethodPointer object to the OBEX earlier this month. It is located at http://obex.parallax.com/objects/697/ .
  
  It was discussed in the thread at http://forums.parallax.com/showthread.php?128397-Callbacks-and-Method-Pointers-in-Spin&highlight=pointer . The technique I use doesn't modify the method tables or the Spn bytecodes (except for a small amount done at initialization). It just requires a 4-word buffer for each method pointer that is used.
  
  Dave
• jazzed Posts: 11,803

  2011-01-27 17:34 edited 2011-01-27 17:34

  Just use the object array unbounded method.
  

  obj
    ' normal code
    serial           : "FullDuplexSerial"
    ' insert other normal object here
  
    ' unbound method code is last
    objarray[1] : "method0" ' contains PUB method to call per array index
    opt1method  : "method1" ' contains PUB method to call per array index
    opt2method  : "method2" ' contains PUB method to call per array index
    optNmethod  : "methodN" ' contains PUB method to call per array index
    ' no more objects
  

  
  Call method by object index. This has risks of course like if Parallax updates the compiler to do object array bounds checks - one would hope that our list of desirable enhancements might get addressed first. YMMV.
• RossH Posts: 5,578

  2011-01-27 17:43 edited 2011-01-27 17:43

  jazzed wrote: »

  Just use the object array unbounded method.
  

  obj
    ' normal code
    serial           : "FullDuplexSerial"
    ' insert other normal object here
  
    ' unbound method code is last
    objarray[1] : "method0" ' contains PUB method to call per array index
    opt1method  : "method1" ' contains PUB method to call per array index
    opt2method  : "method2" ' contains PUB method to call per array index
    optNmethod  : "methodN" ' contains PUB method to call per array index
    ' no more objects
  

  
  Call method by object index. This has risks of course like if Parallax updates the compiler to do object array bounds checks - one would hope that our list of desirable enhancements might get addressed first. YMMV.

  
  Very cute! I had forgotten all about object arrays - thank goodness for languages that do not do any bounds checking!
  
  Ross.